Outcome of computer-assisted surgery in patients with chronic rhinosinusitis

Abstract Objective: To compare the complication rates and outcome of computer-assisted versus non-computer-assisted functional endoscopic sinus surgery. Methods: We reviewed retrospectively the medical records of 276 patients who had undergone sinus surgery for chronic rhinosinusitis with (n=108) or without (n=168) computer assistance, from 1996 to 2004, to determine the incidence of complications and need for revision surgery. Results: The incidence of complications was 6.5 per cent in the computer-assisted group and 6.0 per cent in the non-computer-assisted group (p=1.00). In the computer-assisted group, 9.2 per cent needed revision surgery, compared with 10.7 per cent in the non-assisted group (p=0.84). Conclusions: Although our study found no significant difference in complications or revision rates, computer-assisted surgery serves as an important orientation aid during functional endoscopic sinus surger

Computerassistierte Chirurgie der Nasennebenhöhlen und der vorderen Schädelbasis

Zusammenfassung: Endoskopische oder mikroskopische Eingriffe bei chronischen Nasennebenhöhlenentzündungen mit oder ohne Polyposis sind in der täglichen Praxis häufig. Da es sich um delikate und schwierige minimal-invasive Eingriffe bei engem Raum, Tunnelblick von 4-mm-Endoskopen und häufig leicht blutendem Gewebe bei chronisch entzündlichen Erkrankungen handelt, ist die Orientierung in diesem "Labyrinth" oft schwierig. Bei Rezidiven von Nasenpolypen oder Tumoren sind oft die normalen anatomischen Landmarken, welche dem Chirurgen als Orientierung dienen, nicht mehr vorhanden. Die Navigation zusammen mit den Bildgebungsverfahren wie CT und MRT hilft bei unübersichtlichen Verhältnissen dem Chirurgen, sich im Raum zu orientieren und die Operation umso sicherer und z.T. auch schneller durchzuführen. Zusätzlich hat die Navigation ein großes Potenzial für Ausbildungszweck

Effects of temporal fine structure preservation on spatial hearing in bilateral cochlear implant users

Typically, the coding strategies of cochlear implant audio processors discard acoustic temporal fine structure information (TFS), which may be related to the poor perception of interaural time differences (ITDs) and the resulting reduced spatial hearing capabilities compared to normal-hearing individuals. This study aimed to investigate to what extent bilateral cochlear implant (BiCI) recipients can exploit ITD cues provided by a TFS preserving coding strategy (FS4) in a series of sound field spatial hearing tests. As a baseline, we assessed the sensitivity to ITDs and binaural beats of 12 BiCI subjects with a coding strategy disregarding fine structure (HDCIS) and the FS4 strategy. For 250 Hz pure-tone stimuli but not for broadband noise, the BiCI users had significantly improved ITD discrimination using the FS4 strategy. In the binaural beat detection task and the broadband sound localization, spatial discrimination, and tracking tasks, no significant differences between the two tested coding strategies were observed. These results suggest that ITD sensitivity did not generalize to broadband stimuli or sound field spatial hearing tests, suggesting that it would not be useful for real-world listening

The endoscopic anatomy of the cochlear hook region and fustis: Surgical implications

The cochlear hook region can be considered as the interface between the middle and inner ear. The identification of surgically-relevant endoscopic landmarks of this anatomical entity and assessment of their clinical value is still lacking in the literature. Procedures like cholesteatoma surgery and minimal invasive endoscopic approaches to the lateral skull base may particularly benefit from these considerations. We hypothesize that the spatial orientation of anatomical landmarks in the cochlear hook can be expressed in angles and are reproducibly identifiable by transcanal otoendoscopy. Therefore, endoscopic dissection of the cochlear hook region was performed in 32 temporal bone specimens. Topographic anatomy was documented and analysed. We performed computed tomography of 28 specimens to assess the region in three-dimensional reconstructions. The mean angle between the round window and the basal scala tympani was assessed 25.9\ub0 in endoscopic and 28.2\ub0 in three-dimensionally reconstructed models. The fustis was recognised as a reliable landmark for the basal turn. A mean angle of 155.4\ub0 to the basal scala tympani was assessed. A slight bulging without obstruction of the basal turn was observed in 5 cases. The utility of the revealed anatomical details was assessed in minimal invasive endoscopic lateral skull base approaches. In conclusion, we described the angles between anatomical landmarks of the cochlear hook region. Moreover, the angle as recorded through an endoscope was found to be reliable compared to three-dimensional reconstructions from computed tomography

Limitations of balloon sinuplasty in frontal sinus surgery

Balloon sinuplasty is a tool that is used to treat selected patients with paranasal sinus pathologies. No studies have investigated the aetiology of failed access to the frontal sinus. The aim of our study was to specify the intraoperative technical failure rate and to analyse the aetiology of the failed access to predict potential technical difficulties before surgery. We retrospectively analysed the charts of patients who underwent balloon sinuplasty from November 2007 to July 2010 at three different ENT-Centres. CT-analysis of the patients with failed access was performed. Of the 104 frontal sinuses, dilation of 12 (12%) sinuses failed. The anatomy of all failed cases revealed variations in the frontal recess (frontoethmoidal-cell, frontal-bulla-cell or agger-nasi-cell) or osteoneogenesis. In one patient, a lymphoma was overlooked during a balloon only procedure. The lymphoma was diagnosed 6months later with a biopsy during functional endoscopic sinus surgery. In complex anatomical situations of the frontal recess, balloon sinuplasty may be challenging or impossible. In these situations, it is essential to have knowledge of classical functional endoscopic sinus surgery of the frontal recess area. The drawbacks of not including a histopathologic exam should be considered in balloon only procedure

Navigation und Robotik an der Otobasis

Zusammenfassung: Die bildgestützten computerassistierten mikroskopischen Eingriffe an der Otobasis stellen einen seltenen Eingriff in der täglichen Praxis dar. Es handelt sich jedoch um delikate und schwierige minimalinvasive Eingriffe, da die Orientierung im Felsenbein bis zur Felsenbeinspitze oft schwierig ist. Bei Malformationen oder Tumoren sind die normalen anatomischen Landmarken, die dem Chirurgen als Orientierung dienen, häufig nicht vorhanden. Die Navigation, zusammen mit den bildgebenden Verfahren wie CT, MRT und Angiographie, hilft dem Chirurgen, sich bei unübersichtlichen Verhältnissen im Raum zu orientieren, um die Operation auf diese Weise sicherer und z.T. auch schneller durchzuführen. Weltweite einheitliche Indikationen zum Einsatz an der Otobasis fehlen aber. Die navigationsgestützte Miniaturrobotik ist noch in den ersten praktischen Testphase

Novel surgical and radiological classification of subtympanic sinus: implications for endoscopic ear surgery

Objective The aim of this study is to describe the endoscopic anatomy of the subtympanic sinus (STS), establish a classification according to its extension regarding the level of the facial nerve (FN), and assess the feasibility of the transcanal endoscopic approach to the STS. Study Design Experimental anatomic research. Setting Temporal bone laboratory. Methods We performed endoscopic dissection of 34 human whole head and ear block specimens. Of those, 29 underwent high-resolution computed tomography. The STS was classified according to its extension regarding the level of the FN: type A, no extension medial to the FN; type B, extension to the medial limit of the FN; type C, extension of the sinus medially and posteriorly from the FN into the mastoid cavity. Results The majority of cases (n = 21, 72%) showed a shallow type A STS. We observed a deep type B configuration in 6 cases (21%) and a type C in 2 cases (7%). The STS was completely exposable with a 0\ub0 endoscope in 44% of the specimens. Using a 45\ub0 endoscope, we gained complete insight in 79%. However, in 21% of the cases, the posteromedial extension of the STS was too deep to be completely explored by an endoscopic transcanal approach. Conclusion The majority of the STS is shallow and does not extend medially from the FN. This morphologic variant allows complete transcanal endoscopic visualization. In more excavated STS, a complete endoscopic exploration is not achievable, and a retrofacial approach may be adopted to completely access the STS

Computer-Assisted Precision Surgery in the Ear

Chirurgische Eingriffe am Ohr stellen aufgrund der komplexen Anatomie und der Grössenverhältnisse der beteiligten anatomischen Strukturen eine Herausforderung für den HNO-Chirurgen dar. In diesem Beitrag wird ein Ansatz für die roboterbasierte Navigation zur Hörgeräteimplantation vorgestellt. Insbesondere wird auf die Möglichkeit des Fräsens von Implantatlagern im Felsenbein eingegangen. Je präziser ein Implantat im Schädel verankert werden kann, desto einfacher ist der chirurgischen Ablauf. Weiterhin, profitieren Patienten von verkürzten Operationszeiten und weniger schmerzhaften Eingriffen.Traditional surgical procedures involving the implantation of artificial hearing devices in the inner ear are challenging due to the size and complexity of anatomical structures within the temporal bone. To date, no stereotactic instrument guidance technology providing the necessary levels of accuracy is available. This work presents an approach to robot assisted implantation of hearing devices. Specifically, the robot system was used to milla cavity to for a direct acoustical stimulation implant. As the precision of such cavities increases, so also can future implant generations improve in terms of size, complexity and cost effectiveness. Additionally, patients themselves would profit from shorter procedure times and less painful interventions

Discovering middle ear anatomy by transcanal endoscopic ear surgery: A dissection manual

The middle ear is located in the center of the temporal bone and bears a highly complex anatomy. The recently introduced exclusively endoscopic transcanal approach to the middle ear is a minimally invasive technique sparing the bone and mucosa of the mastoid bone, since the middle ear is accessed through the external auditory canal. This emerging method has several advantages over the traditional (microscopic) approaches to the middle ear such as the panoramic wide-angle views of the anatomy, the possibility to approach and magnify tiny structures, and the possibility of looking around the corner using angled endoscopes. The cadaveric dissection method presented here consists of an overview on the technical requirements and a precise description of a step-by-step protocol to discover the anatomy of the middle ear. Each step and anatomical structure is carefully described in order to provide a comprehensive guide to endoscopic ear anatomy. In our opinion, this is particularly important to any novice in endoscopic ear surgery as it provides thorough anatomical knowledge and may improve surgical skills

Quantification and Comparison of Droplet Formation During Endoscopic and Microscopic Ear Surgery: A Cadaveric Model

Objectives: The COVID-19 pandemic and the disproportional spread of the disease among otorhinolaryngologists raised concerns regarding the safety of health care staff. Therefore, a quantitative risk assessment for otologic surgery would be desirable. This study aims to quantitatively compare the risk of perioperative droplet formation between microscopic and endoscopic approaches. Study Design: Experimental research. Setting: Temporal bone laboratory. Methods: The middle ear of whole head specimens was injected with fluorescein (0.2 mg/10 mL) before endoscopic and microscopic epitympanectomy and mastoidectomy. Fluorescent droplet deposition on the surgical table was recorded under ultraviolet light, quantified, and compared among the interventions. Drilling time, droplet proportion, fluorescein intensity, and droplet size were assessed for every procedure. Results: A total of 12 procedures were performed: 4 endoscopic epitympanectomies, 4 microscopic epitympanectomies, and 4 mastoidectomies. The mean (SD) proportion of fluorescein droplets was 0.14‰ (0.10‰) for endoscopic epitympanectomy and 0.64‰ (0.31‰) for microscopic epitympanectomy. During mastoidectomy, the deposition of droplets was 8.77‰ (6.71‰). Statistical comparison based on a mixed effects model revealed a significant increase (0.50‰) in droplet deposition during microscopic epitympanectomy as compared with endoscopic epitympanectomy (95% CI, 0.16‰ to 0.84‰). Conclusions: There is considerable droplet generation during otologic surgery, and this represents a risk for the spread of airborne infectious diseases. The endoscopic technique offers the lowest risk of droplet formation as compared with microscopic approaches, with a significant 4.5-fold reduction of droplets between endoscopic and microscopic epitympanectomy and a 62-fold reduction between endoscopic epitympanectomy and cortical mastoidectomy